Apparatus for forming spiral steel pipe

ABSTRACT

An improved apparatus for forming spiral steel pipe by pressing a steel strip against exterior forming rolls by mandrel rolls so as to bend the steel strip spirally. A freely movable truck has the exterior forming roll supporting stands fixedly mounted on the upper surface thereof, and is movably mounted on rails on the base of the apparatus. The rails having raisable and lowerable portions at the positions where the truck is supported thereon when the exterior forming rolls are at their operative positions on the apparatus. Clamps along the base are engageable with the truck for fixing the truck at a predetermined position on the base, and supporting frame means is provided adjacent the rails for removably supporting the mandrel roll supporting stand at its operative position above the exterior forming roll supporting stands. With the exterior forming roll supporting stand resting on the base, the rail portions can be raised and the mandrel roll supporting stand removed from the supporting frame means to rest on the exterior forming roll supporting stand, and the truck can be moved along the rails to remove both stands from the apparatus, and the stands can be replaced in the apparatus by a reverse sequence of operations.

United States Patent [1 1 [4 1 Feb. 11,1975

Matsufuji et a1.

1 1 APPARATUS FOR FORMING SPIRAL STEEL PIPE I76] Inventors: AklraMatsufuji, l-7-15, Sawami,

Tobata-ku, Kitakyushu; Kenji Numajiri, 2406, Oaza Hikino, Yawata-ku,Kitakyushu, both of Japan [22] Filed: Nov. 28, 1972 [21] Appl. No.:310,082

[30] Foreign Application Priority Data Nov. 29, 1971 Japan 46-96514 July18, 1972 Japan ..47-8530() [52] US. Cl 72/135, 29/4773, 72/448 [51] int.C1. B21c 37/12 [58] Field of Search 72/49, 50, 135, 448; 100/299, DIG.18; 29/477.3

[56] References Cited UNITED STATES PATENTS 2,675,773 4/1954 Carr 72/502,913,946 11/1959 Ellrich 83/630 2,988,234 6/1961 Barothy... 214/12,996,025 8/1961 Georgeff..... 72/446 3,146,331 8/1964 Schubert.. 72/1353,207,065 9/1965 Dan1y....... 100/229 3,212,430 10/1965 Clements. 100/353,407,639 10/1968 Kehne 72/135 3,427,854 2/1969 Michelson... 72/4483,650,015 3/1972 Davis 29/4773 Primary Examiner-C. W. Lanham AssistantExaminer-Gene P. Crosby Attorney, Agent, or Firm-Wenderoth, Lind &Ponack [57] ABSTRACT An improved apparatus for forming spiral steel pipeby pressing a steel strip against exterior forming rolls by mandrelrolls so as to bend the steel strip spirally. A freely movable truck hasthe exterior forming roll supporting stands fixedly mounted on the uppersurface thereof, and is movably mounted on rails on the base of theapparatus. The rails having raisable and lowerable portions at thepositions where the truck is supported thereon when the exterior formingrolls are at their operative positions on the apparatus. Clamps alongthe base are engageable with the truck for fixing the truck at apredetermined position on the base, and supporting frame means isprovided adjacent the rails for removably supporting the mandrel rollsupporting ations.

5 Claims, 8 Drawing Figures I @PATENTEDFE'B'I 191s SHEET 30F 3 FIG. 5.PRIYYOR- ART .v w w I Em i!! APPARATUS FOR FORMING SPIRAL STEEL PIPEBACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to an apparatus for forming spiral steel pipe, moreparticularly to such a device for replacing the forming roll supportingstands having the outer surface forming rolls and inner surface formingrolls thereon with accuracy in a desired position and in a short time,and also to a screw down device for the apparatus.

2. Description of the Prior Art Acccording to the conventional art priorto the present invention, the replacement of stands for forming a spiralsteel pipe is carried out by separately removing the inner surfaceforming roll support stand equipped with inner surface forming ormandrel rolls and the outer surface forming roll support stand equippedwith outer surface forming rolls from the apparatus, adjusting them andagain placing them back in the apparatus. The mounting of the thusadjusted stands in the limited space of the apparatus, as well asputting them back therein requires a long time and much labor. Besides,in the mounting of the stands, it is difficult to have them reinstalledwith accuracy at the right positions, such difficulty affecting the sizestabilization of the spiral steel pipe produced.

The screw down device for the conventional type of the apparatus forforming spiral steel pipe, which is driven through a screw 24 and a nut25 as shown in FIG. 5, or by using a cotter or the like, is soconstructed as to apply a forming force to the mandrel roll stand 22through the two screw down rods 26 and 27, and have it balanced at thebalancing point in the vicinity of its center by the balance rod 28which is always exerting a pulling force by means of an oil pressurecylinder (not shown in the drawings) or a spring.

When spiral steel pipe is formed of steel sheets of various widths byusing one and the same apparatus of a conventional type, no greatdislocation takes place of the position 'of screw down device on theforming stand from the position of the forming stand so that the mandrelrolls on the stand can work on steel sheet, even though the screw downrods are fixed, as described above, since the forming point is near thecenter of the steel sheet.

However, the operation using such a forming point as described above,requires additional work for adjusting the pre-treatment devices for thesteel sheet such as the side-trimmer to accommodate various widthsthereof.

Therefore, the recent trend has been toward the use of a forming pointL," that is, the forming point has been located in an increasing numberof cases at the left end of the material steel sheet in the direction ofoperation.

This method has an advantage that such pretreatment devices for thesteel sheet as side trimmer can remain fixed. However the operation ofthe device with the forming point L as shown in FIG. 5, tends to cause agreat dislocation of the screw down position from the forming position,producing deformation due to the forming force'on the mandrel rollforming stand.

SUMMARY OF THE INVENTION For obviating the abovementioned difficultyinherent in the prior art, the present invention provides an apparatusfor forming spiral steel pipe which has a mandrel roll stand and theouter surface forming roll stand which are both adjustable andreplaceable with great ease and in a very short time.

Another object of the present invention is to provide an apparatus forforming spiral steel pipe which is equipped with a mandrel roll standand an outer surface forming roll stand both of which are adjustable andreplaceable with high accuracy in set positions during reinstallment.

Another object of the present invention is to provide an apparatus forforming spiral steel pipe from a variety of steel sheets, with extremelylittle deformation of the so formed pipe caused by the forming force ofthe mandrel roll stand.

These objects and other objects of the present invention will becomeapparant from the following description of embodiments with reference tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan of an apparatusfor-forming spiral steel pipe acccording to the present invention.

FIG. la is a partial plan view ofa portion of the apparatus positionedabove the apparatus as shown in FIG. 1.

FIG. 2 is a side view of the apparatus shown in FIG. I.

FIG. 3 is a sectional view taken on line III III of FIG. 2.

FIG. 4 is a front view of the apparatus shown in FIG. 1.

FIG. 5 is a side view of an apparatus according to the prior art forforming spiral steel pipe showing the screw down device for the innersurface forming roll stand.

FIG. 6.is a side view of the screw down device for the inner surfaceforming roll stand according to the present invention.

FIG/7 is a sectional view of the screw down device shown in FIG. 6 alongthe line Vll VII.

DESCRIPTION OF THE PREFERRED EMBODIMENT The following is a detaileddescription of the preferred embodiment of the present invention withreference to drawings:

As shown in FIGS. 1 and 2, the exterior forming roll stands 20 have agreat number of parallel exterior forming rolls 21 freely rotatablymounted on the upper surface of said stands 20, spaced along the longdirection of said stands 20, with the axis of each of said rolls 20being oblique to the long direction of said stands 20. On the lowersurface of the interior forming roll, or mandrel roll, stand 22, thereare a great number of mandrel rolls 23 mounted in the same manner as theexterior forming rolls 21 on the exterior forming stands 20. One seriesof mandrel rolls 23 is placed right over two series of exterior formingrolls 21 in a pyramid-like arrangement when viewed sectionally, as seenin FIGS. 3 and 4. Steel strip S is then fed between the two kinds ofrolls, that is between the exterior forming rolls 21 and the mandrelrolls 23, obliquely to the long direction of both stands, that is, theexterior forming stand 20 and the interior forming stand 22, in adirection along these rolls 21 and 23. The steel strip S is then pressedagainst the exterior forming rolls on stands 20 by the mandrel rolls onstand 22 which is forced down by a screw down device (not illustrated),the strip thus being bent so as to form pipe P, shown in phantom lines.

An outer surface forming roll supporting stand 20 having the outersurface forming rolls 21 thereon, is fixed, by means of bolts, wedgegrips, etc., on the upper surface of a truck 2 for the transportation ofthe main part of the forming apparatus of the present invention(hereafter called the truck"), said truck 2 being freely movable onrails and 6, which are laid in the long direction of the base 1 of theforming apparatus. In this case, the base 1 of the apparatus is a standfor setting said truck 2 at the position right for the operation of theapparatus.

Said rails 5 and 6 for the movement of said truck 2 may be the normaltype, so far as they are effective for the prevention of side-swingingand derailing. In this case, one of said rails 6 has a flat head, andthe other has the head shaped like an inverted letter V. Clamps 7 areprovided according to the requirement at appropriate positions on bothsides of the base 1 for the fixation of said truck 2 to the base 1. Theyneed not be a particular kind, but in this embodiment, each clampconsists of a cylinder 9 for setting into operation and releasing arms 8holding the truck 2 and another cylinder 10 for moving the arms 8 up anddown, so as to fix the truck 2 on the base 1, as shown in FIG. 4.

In FIG. 2 and FIG. 3, raisable and lowerable rail portions 11 and 12make up parts of said rails 5 and 6 within the base 1, on which portionsguiding wheels 3 and 4 on the truck 2 are positioned when the truck 2stops against stops 15.

The raisable and lowerable rail portions 11 and 12 are moved up and downby means of fluid pressure cylinders 13 and 14, so that when they move,they can be brought level with said rails 5 and 6; therefore, theirheads are respectively the same in shape as those of said rails 5 and 6.Stops 15 provided at one end of the base 1 position said truck 2 at theright position on the base 1. A truck pushing device is provided whichconsists of a pushing arm 17 with one end pivoted for free rotation onthe stand and of a pushing cylinder 18 for pressing said pushing arm 17in the vicinity of its center; said device 16 is provided at the end ofthe base 1 opposite to the position of the stops 15, for the adjustmentof the location of said truck 2 in the long direction of the apparatusthen the truck 2 is placed on the base 1. The truck pushing device 16may function as a clamp, in addition to pushing of the truck 2.

An inner surface forming roll or mandrel roll, stand having innersurface forming rolls 23 mounted thereon, is held firmly by holdingframes 19 on each side of the base 1.

The mandrel roll stand 22 is releasably supported on the holding frames19 through housing 29 by a supporting frame 22, which in turn isreleasably clamped to the upright holding frames 19 by pivotable clampmember 19 mounted on the holding frames 19.

In the apparatus of the present invention, the replacement of formingstands is so carried out that in the first place, the mandrel rollsupporting stand 22 is released from the holding frames 19, and isplaced on the outer surface forming roll supporting stand 20, and thenall the clamps 7 are released and the rail portions 11 and 12 are movedup respectively by the cylinders 13 and 14 until they are level withsaid rails 5 and 6 for connection therewith. At the same time, saidtruck 2 moves up on its guiding wheels 3 and 4 to the level of the rails5 and 6. In other words, said truck 2 is so placed as to run on therails 5 and 6.

Then, by using any appropriate type of trailer (not shown in thedrawings), the truck 2 is rolled off the base 1. Then. the truck 2 maybe replaced by another truck 2 already having an outer surface formingroll supporting stand 20 and a mandrel roll supporting stand 22, or itmay have another outer surface forming roll supporting stand 20 andanother mandrel roll supporting stand 22 mounted thereon and moved backonto the base 1 by the trailer (not shown in the drawings), whichever isconvenient.

The replacing of the truck 2 with the new or substituted stands thereon,is complete when the truck stops against the stops 15. At that time, theportions 11 and 12 of the rails 5 and 6 respectively supporting theguiding wheels 3 and 4 of the truck 2 are moved down respectively by thecylinders 13 and 14 so as to lower the truck 2 onto the base 1. As thereare concavities made in the bottom of the truck 2 they are engaged withconvexities of the rails 5 and 6, setting the truck 2 firmly at theright position and preventing its side-dislocation during the forming ofthe spiral pipes.

Then, the position of the truck 2 in the long direction of the apparatuswhen the truck 2 is lowered onto the base 1, is adjusted by pushing thetruck 2 against the stops 15 again and again by means of the truckpushing device 16. After that, the truck 2 is fixed on the base 1 withthe clamps 7.

On the other hand, the mandrel roller supporting stand 22 isdisconnected from the temporary connection with the outer surfaceforming roll supporting stand 20, and is fixed to the holding frames 19at the proper position.

In reference to FIG. 6 one embodiment of the screw down device for themandrel roller supporting stand according to the present invention isshown.

A balance rod 28 extends downwardly from above toward the vicinity ofthe central part of the stand 22, and the lower end is connected to saidcentral part of the stand 22 and the top is connected with a liquidpressure cylinder or spring (not illustrated). The stand 22 receivesupward force produced by said liquid pressure cylinder or spring andtransmitted through said balance rod 28, so as to balance said stand 22against a downward screw down force. Housing 29 is releasably mounted onsaid supporting frames 19 and on housing 29 are mounted said downwardscrew down force producing means and said liquid pressure cylinder orspring. Screw down rods 26 and 27 supply forming force to the stand 22,both of which are set by a screw 24, and are rotated by the drivingforce supplied from a power source (not shown) through nuts 25 attachedto the housing 29, releasably mounted on supporting frames 19,generating the forming force. A screw down device using a cotter insteadof a screw is also useful for this purpose. The abovementioned two screwdown rods 26 and 27 are connected to each other by a screw downconnection beam 30; and one of the rods 26 and 27 the screw down rod 26placed in the vicinity of the end of the stand 22 has an end piece 31freely movable along the screw down connection beam 30 toward the screwdown rod 27, say, as far as the position 32 shown in the drawing.

The movable connection means between the end piece 31 of the screw downrod and the screw down connection beam 30 and between the end piece 31of the screw down rod and the forming stand 22, are the form of dovetailgrooves as shown in FIG. 7. But such means are not limited to thisconstruction. Set screws 33 and 34 are provided for fixing the end piece31 to the stand 22 at the right positions. The movement of the end piece31 of the screw down rod 26 depending on the width of the steel sheets Smay be made automatically or manually, whichever is convenient.

What is claimed is:

1. In an apparatus for forming spiral steel pipe by pressing a steelstrip against exterior forming rolls by mandrel rolls so as to bend saidsteel strip spirally, the mandrel rolls being mounted on a mandrel rollsupporting stand and the exterior forming rolls being mounted onexterior forming roll supporting stands, the mandrel roll supportingstand being above the exterior forming roll supporting stands, theimprovement comprising a freely movable truck having said exteriorforming roll supporting stands fixedly mounted on the upper surfacethereof, rails on the base ofthe apparatus on which said truck ismovably mounted, said rails having raisable and lowerable portions atthe positions where said truck is supported thereon when said exteriorforming rolls are at their operative positions on the apparatus, clampsalong said base engageable with said truck for fixing said truck at apredetermined position on the base, and supporting frame means adjacentsaid rails for releasably supporting said mandrel roll supporting standat its operative position above said exterior forming roll supportingstands, whereby with the exterior forming roll supporting stand restingon said truck, said rail portions can be raised and said mandrel rollsupporting stand released from said supporting frame means to rest onsaid exterior forming roll supporting stand, and said truck can be movedalong said rails to remove both stands from the apparatus, and thestands can be replaced in the apparatus by a reverse sequence ofoperations.

2. The improvement as claimed in claim 1 in which said rail portionscomprise fluid pressure operated piston-cylinder means for raising andlowering the rail portions.

3. The improvement as claimed in claim 1 in which said clamps eachcomprise a clamp member mounted on said base for movement up and downrelative to said truck, first fluid pressure piston-cylinder meanscoupled to said clamp member for moving said clamp up and down and asecond fluid pressure piston-cylinder means coupled to said clamp forurging said clamp member toward said truck for tightly engaging saidclamp member with said truck.

4. The improvement as claimed in claim 1 in which said base has a stopthereon against which said truck abuts when it is in the operativeposition, and a truck pushing means at the opposite end of the base fromthe stop for urging said truck into engagement with said stop.

5. The improvement as claimed in claim 1 in which a screw downconnection is provided for mounting said mandrel roll supporting stand,said screw down connection comprising a pair of screw down rods spacedalong the length of the mandrel roll supporting stand and a connectingbeam extending between said screw down rods, one of said screw down rodshaving at least a portion thereof movably connected to said connectingbeam for movement along said beam toward the other screw down rod.

1. In an apparatus for forming spiral steel pipe by pressing a steelstrip against exterior forming rolls by mandrel rolls so as to bend saidsteel strip spirally, the mandrel rolls being mounted On a mandrel rollsupporting stand and the exterior forming rolls being mounted onexterior forming roll supporting stands, the mandrel roll supportingstand being above the exterior forming roll supporting stands, theimprovement comprising a freely movable truck having said exteriorforming roll supporting stands fixedly mounted on the upper surfacethereof, rails on the base of the apparatus on which said truck ismovably mounted, said rails having raisable and lowerable portions atthe positions where said truck is supported thereon when said exteriorforming rolls are at their operative positions on the apparatus, clampsalong said base engageable with said truck for fixing said truck at apredetermined position on the base, and supporting frame means adjacentsaid rails for releasably supporting said mandrel roll supporting standat its operative position above said exterior forming roll supportingstands, whereby with the exterior forming roll supporting stand restingon said truck, said rail portions can be raised and said mandrel rollsupporting stand released from said supporting frame means to rest onsaid exterior forming roll supporting stand, and said truck can be movedalong said rails to remove both stands from the apparatus, and thestands can be replaced in the apparatus by a reverse sequence ofoperations.
 2. The improvement as claimed in claim 1 in which said railportions comprise fluid pressure operated piston-cylinder means forraising and lowering the rail portions.
 3. The improvement as claimed inclaim 1 in which said clamps each comprise a clamp member mounted onsaid base for movement up and down relative to said truck, first fluidpressure piston-cylinder means coupled to said clamp member for movingsaid clamp up and down and a second fluid pressure piston-cylinder meanscoupled to said clamp for urging said clamp member toward said truck fortightly engaging said clamp member with said truck.
 4. The improvementas claimed in claim 1 in which said base has a stop thereon againstwhich said truck abuts when it is in the operative position, and a truckpushing means at the opposite end of the base from the stop for urgingsaid truck into engagement with said stop.
 5. The improvement as claimedin claim 1 in which a screw down connection is provided for mountingsaid mandrel roll supporting stand, said screw down connectioncomprising a pair of screw down rods spaced along the length of themandrel roll supporting stand and a connecting beam extending betweensaid screw down rods, one of said screw down rods having at least aportion thereof movably connected to said connecting beam for movementalong said beam toward the other screw down rod.